The document discusses various topics related to aquatic ecosystems: - Oceans cover 71% of the Earth's surface and have an average depth of 3.7 km, with the deepest part being the Mariana Trench at 11,000 meters. - The United Nations Convention on the Law of the Sea (UNCLOS) established rules governing the ocean and created new institutions. - Wetlands provide important ecosystem services but 87% have been lost, threatening dependent species. The Ramsar Convention promotes wetland conservation. - Aquatic food webs include plankton, benthos, nekton, fish, and humans that consume from all levels. Climate change poses threats like rising sea levels, warming, and

1. Aquatic Ecosystem
Sesion-7:
Environmental Studies & Disaster
Management
Prof. Ajay Mohan Goel
ajay.goel@bmu.edu.in

2. Non-Quiz
1. Ocean covers ________ of the earth’s surface
2. The average depth of oceans is ____________ Km.
3. Deepest part of Ocean is ____________ in __________ Ocean with a depth of __________
Metres.
4. UNCLOS is an acronym for the ___________________________________.
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3. Non-Quiz
1. Ocean covers 71% of the earth’s surface
2. The average depth of oceans is 3.7 Km.
3. Deepest part of Ocean is MarinaTrench in
Pacific Ocean with a depth of 11,000
Meters.
4. UNCLOS is an acronym for the United
Nations Convention for the Law of the
Sea.
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4. United Nations Convention for the Law of the Sea.
• The Convention has created three new institutions on the international scene :
• The InternationalTribunal for the Law of the Sea, headquartered in Hamburg (Germany),
• The International Seabed Authority, headquartered in Kingston (Jamaica),
• The Commission on the Limits of the Continental Shelf, based in the United Nations
Headquarters in NewYork.
• The Convention came into effect in November, 1994. It now has 162 Parties including the
European Union for its share of jurisdictions.
• USA is not a Member
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5. Wetlands
• A land area saturated with water, permanently
or seasonally
• Includes:
• swamps, marshes
• billabongs, lakes, lagoons
• saltmarshes, mudflats
• mangroves, coral reefs, estuaries
• bogs, fens, and peatlands
• May support both aquatic and terrestrial species.
• The prolonged presence of water creates
conditions:
• that favor the growth of specially adapted
plants (hydrophytes)
• promote the development of characteristic
wetland soils.
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6. Wetlands - Ramsar Convention’s definition
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7. Wetlands
• Provide us water,
• Protect us from floods, droughts and other disasters,
• Provide food and livelihoods to millions of people,
• Support rich biodiversity
• Store more carbon than any other ecosystem.
• Contribute directly or indirectly to 75 SDG indicators
• Complex biogeochemical processes maintain functional wetland ecosystems
Yet, the value of wetlands remains largely unrecognized by policy and decision makers.
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8. Wetlands
• Up to 87% of the global wetland resource has been lost since 1700.We lose wetlands three
times faster than natural forests.
• Wetland-dependent species are in serious decline. Since 1970, declines have affected 81% of
inland wetland species populations and 36% of coastal and marine species.
• The loss of wetlands continues with direct and measurable negative impacts on the quality
and availability of water, food security, biodiversity and carbon sequestration.
The Ramsar Convention promotes wetland conservation and wise use and is at the centre of
efforts to halt and reverse wetland loss.
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9. Add a footer

10. Ecosystem services from wetlands
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11. Wetlands of International Importance throughout the world.
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12. ECOLOGICAL CHARACTER OF WETLANDS (RAMSAR CONVENTION 2005)
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13. Ramsar has a key role in
supporting the Sustainable
Development Goals
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14. List of 37 Ramsar Sites - India
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15. Wetlands in India
•India's prominent wetlands:
• Chilika lake (Odisha)
• Wular lake (J&K)
• Renuka (Himachal Pradesh)
• Sambhar Lake (Rajasthan)
• Deepor Beel (Assam)
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16. Marshes and Swamps
Swamp Marsh
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17. Billabongs Lagoon
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18. Salt Marshes Mudflats (Picture of Rann of Kutch)
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19. Mangroves
Bhitarkanika Mangroves, Odisha Godavari – Krishna Mangroves
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20. Bogs, Fens & Peats
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Coral Reefs

21. Urban Wetlands
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22. Aquatic Ecosystem
• Kinds of Organisms
• Plankton:
• Phytoplankton: photosynthetic producers of the
ocean
• Zooplankton: primary consumers, feeding on
phytoplankton
• Benthos
• Bottom dwellers – adapted to live on the ocean’s
floors E.g. sponges, oysters, barnacles
• Burrow into sand :Worms, clams
• Move on the floor: crawfish, brittle stars
• Nekton
• Large organisms: Fish, turtles, whales
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23. Aquatic Food Webs
• Describe who eats whom in an ecological community.
• Humans consume aquatic life from every section of this food web.
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Large sharks,
billfish, dolphins,
toothed whales,
and large seals
Fish, small sharks,
corals, and baleen
whales
Primary consumers
like zooplankton,
small fish, and
crustaceans.
Phytoplankton and
algae
Humans consume aquatic life from every section of this food web.

24. Oceans
• Only ~15% explored and mapped
• Contain > 250,000 species of plants & Animals
• Rate at which undiscovered species are being
found shows no signs of slowing.
Greatest threats to marine biodiversity around the
world
• Past & Existing
• Overfishing,
• Habitat loss,
• Invasive species and
• Pollution
• emerging threats,
• Rising water temperatures
• Ocean acidification.
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25. Largest extinction in Earth's history
End of the Permian Period (~252 million years ago)
• Geochemical evidence provides strong support for rapid global warming and
accompanying ocean oxygen (O2) loss
• The combined physiological stresses of ocean warming and O2 loss largely account for the
spatial pattern and magnitude of extinction observed in the fossil record of the “Great
Dying.”
• These results highlight the future extinction risk arising from a depletion of the ocean’s
aerobic capacity that is already under way.
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26. Why is sea level rising?
• The two major reasons
• Thermal expansion of ocean waters as they warm
• Increase in the ocean mass, principally from land-based sources of ice (glaciers and ice caps
and the ice sheets of Greenland and Antarctica).
• Global warming from increasing greenhouse gas concentrations is a significant driver of both
contributions
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27. Projections of future sea level change
• Sea level will continue to rise due to:
• Warming from both past (twentieth century and earlier) and twenty-first century
greenhouse gas emissions.
• Ocean thermal expansion is likely to be the dominant contribution to twenty-first century
level rise
• melting of glaciers and ice caps.
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28. Eight priority actions to avert ecological disaster in the global ocean.
• Address climate change: implement policies to limit the temperature rise to 1.5oC, but prepare for a
2-3oC temperature rise.
• Secure a robust, comprehensive High SeasTreaty with a Conference of Parties and a Scientific
Committee.
• Enforce existing standards for effective marine protected areas (MPAs), and in particular fully-
protected marine reserves, and extend their scope to fully protect at least 30% of the ocean, including
representation of all habitats and the high seas, while ensuring effective management to prevent
significant adverse effects for 100% of the rest of the ocean.
• Impose a precautionary pause on deep-sea mining to allow time to gain sufficient knowledge and
understanding to support informed decisions and effective management.
• End overfishing and destructive practices including illegal, unreported and unregulated (IUU) fishing.
• Radically reduce marine water pollution.
• Provide a financing mechanism for ocean management and protection.
• Scale-up scientific research on the ocean and increase transparency and accessibility of ocean data
from all sources (i.e. science, government, industry).
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29. Who owns the world's oceans?
• U.N. Convention on the Law of the Sea.
• Completed: 1982 and came into force: 1994
• International waters remained international, "the common heritage of all mankind"
• Limitations set on how much coastal water and seafloor a nation could claim as its own.
• The territorial sea: aquatic boundary along a nation's coast that extends its terrestrial
boundaries, (12 nautical miles = 13.8 miles or 22.2 km).
• Banning nuclear weapons testing in international waters,
• Concept of Exclusive Economic Zones (EEZ).
• Territorial waters are extensions of a state's laws and right of defence
• EEZs are extensions of a state's rights to resources offshore.The boundaries of an EEZ go
beyond territorial waters, extending 200 miles (322 km) from shore.
• All organic and mineral resources found in these waters are the exclusive domain of the
coastal nation it belongs to.
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30. Who owns the world's oceans?
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31. The International Community Is Losing Ground—As Individual Countries Gain It
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32. International
Governance
Structures for
the Ocean—
Multi-sectoral
Approach and a
Plethora of
Organizations
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33. Thank you
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Prof. Ajay Mohan Goel
ajay.goel@bmu.edu.in